The New Core Small Arms Of Marine Rifle Squads

The U.S. Marine Corps has replaced its standard suite of small arms for Marine Rifle squads with new versions that make incremental improvements over their predecessors.

The new weapons replace Vietnam era and Cold War era designs, that with subsequent relatively minor modifications, the Marine Corps has been using. The M16 entered service in 1964 and its M203 grenade launcher attachment entered service in 1969. The M4, M249, and SMAW recoilless rifle all entered service in 1984. 

The replacement M320 grenade launcher entered service in 2009. The new M27 and M38 entered service in 2010. The M3E1 recoilless rifle entered service in 2019. 

The standard weapon of the Marine rifleman will be the M27 IAR (for Infantry Automatic Rifle) replaces the M16 assault rifle and its smaller derivative that was more common in the Marine Corp immediately prior to the switch, the M4 carbine. It is an incremental improvement that will also include "suppressors" (i.e. silencers), a bipod stand, and an optical sight (with up to 8x power) for each rifle. It was originally designed as a replacement for the belt-fed M249 SAW (squad automatic weapon) using standard ammunition magazines instead, but was repurposed. It uses a 30 round cartridge of the same ammunition as the M4, M16 and M249: a NATO standard 5.56mm x 45mm bullet. Its gas-operated short-stroke piston action with a rotating bolt runs cooler, cleaner, requires less maintenance, has less internal parts wear and is less susceptible to malfunctions compared to previous direct impingement M4/M16 style weapons. 

Fully loaded with 30 rounds, it weighs 9.8 pounds, compared to 7.8 pounds for an M4 with 30 rounds, 8.8 pounds for an M16 with 30 rounds, and 22 pounds for the M249 SAW with 200 rounds. 

The M27 is 33 to 36.9 inches long (depending upon stock extension) v. 30.8 to 33 inches for an M4 (depending upon stock extension), 39.5 inches for an M16, and 40.8-43.8 inches for an M249 (depending on barrel length); so it is intermediate in length between an M4 carbine and an M16 assault rifle, and shorter than an M249.

But the M27 is more accurate with a point target effective range of 600 meters and an area target effective range of 800 meters, than the M4 (effective point target firing range 500 meters), the M16 (effective point target firing range 550 meters), or the M249 (effective area target range of 700-800 meters depending on the barrel length variant, but with area fire only due to its rapid fire rate), although it can fire fewer sustained rounds than the M249. 

Each M27 costs $1,300. The M4 cost $700. The M249 cost $4,087.

So, it provides less noise, less heat, fewer malfunctions, less maintenance, a bit more accuracy, and in the case of the squad's heaviest rifle, less weight.

Each Marine Rifle squad will also have: 

* one M38 SDMR (for Squad Designated Marksman Role) rifle for the member of the squad who is the best shot, which is basically a sniper rifle version of the M27 IAR with a better optical sight and improved suppressor which replaces the semiautomatic SAM-R version of the M16 (it shares the same advantages over its predecessor as the M27);

* one M320 grenade launcher which is a small stand alone grenade launcher (that can also be attached to the underside of a rifle if desired) that delivers a single shot 40mm grenade up to 350 meters (it is the same basic concept as its predecessor, but was designed to be more reliable, ergonomic, accurate, and safer than the predecessor M203 which was also permanently attached to an M4 carbine or M16 rifle); and

* one M3E1 MAAWS (for multi-purpose anti-armor anti-personnel weapon system) which is a single shot recoilless rifle (i.e. bazooka) that fires an 84mm rocket up to 800 meters with a computerized targeting system and is a bit lighter (15 pounds v. 22 pounds) than its predecessor. It is intended to be used against lightly armored targets and enemy soldiers using unfortified buildings as cover. It replaces the similar SMAW system that was more clumsy and unreliable.

Ultimately, the change is not profound. The new weapons figuratively shave the rough edges off their predecessors in ways that make it somewhat less likely that something will go wrong on the battlefield. 

In exchange, Marine Rifle squads sacrifices that high volume of fire belt-fed M249 which was heavy and inaccurate but was intended to be used for "suppressing fire" in lieu of accurate fire that hit enemy targets. Basically, the M249 was designed to keep a numerically superior crowd of opposition soldiers with inferior firepower from charging towards them World War I style, and overwhelming a Marine rifle squad. The Marines decided that this scenario was an increasingly rare one as opposition tactics adapted to modern warfare, and that this capability could be partially compensated for by having the entire rifle square fire their assault rifles in unison at an oncoming horde if necessary.